珠江三角洲城市群三维生态足迹动态变化及驱动力分析

以自然资本利用的存量、流量分类测度的三维生态足迹方法是区域可持续发展能力评估的最新方法论进展.以珠江三角洲城市群9个地市23年的面板数据为数据源,在测度自然资本利用状况时空变化基础上,利用偏最小二乘法进行驱动力分析.研究表明:1珠江三角洲23年间生态足迹呈递增趋势,生态赤字加剧,自身的可持续发展能力较弱;2珠三角自然资本存量占用呈递增趋势;流量资本消耗呈递减趋势,表明过度消耗存量资本换取发展,区域自然资本流动所受的限制较多;3食品消费结构变化、化石能源消费总量增加以及城市扩张带来的土地利用变化,是生态足迹结构变化的主要成因;4人口规模、社会经济差异和政策因素是区域自然资本利用动态变化特征差异的3个主导因素,科技因素和自然环境因素对研究区自然资本利用变化的影响程度不显著.     

Impact of psychological capital on construction worker safety behavior: Communication competence as a mediator

IntroductionConstruction workers face a work environment of high risk and mental stress. Psychological capital (PsyCap) could influence employee's mental health and work performance. It would be helpful to determine whether PsyCap affects worker safety behavior. However, few studies empirically examined the impacts of the sub-dimensions of PsyCap on the safety behavior in construction settings, reducing the potential practicability of PsyCap to improve workplace safety performance. Thus, this study tested the relationship between sub-dimensions of PsyCap (self-efficacy, hope, resilience, optimism) and safety behaviors (safety compliance, safety participation), while the mediating role of communication competence was also explored. Method: Data were collected from 655 construction workers in China using a psychological capital questionnaire (PCQ). The theoretical model were tested with confirmatory factor analyses (CFA) and structural equation modeling (SEM) techniques. Results: Results show that: (a) the self-efficacy dimension of PsyCap positively affected safety compliance and safety participation, while the resilience dimension positively impacted safety participation; (b) the hope dimension was not directly related to safety behaviors, while the optimism dimension negatively associated with safety participation; and (c) communication competence mediated the relationships between the hope and optimism dimensions of PsyCap and safety participation. Conclusions: A multidimensional perspective on PsyCap should be taken while examining its effects on safety behavior and the individual communication competence helps to enhance construction safety. Findings of this study shed lights on safety behavior promotion practices based on the multidimensional model. Initiating flexible psychological capital training and intervention, and strengthening communication skills of construction employees are suggested to improve safety performance in the construction industry.     

Smallholder Agroforestry Systems For Carbon Storage

Most smallholder agroforestry systems in Southeast Asia are tree- and species-rich systems producing non-wood and wood products for both home use and market sale. Due to their high biomass, these systems contain large carbon (C) stocks. While the systems of individual farmers are of limited size, on a per area basis smallholder systems accumulate significant amounts of C, equaling the amount of C stored in some secondary forests of similar age. Their ability to simultaneously address smallholders’ livelihood needs and store large amounts of C makes smallholder systems viable project types under the Clean Development Mechanism (CDM) of the Kyoto Protocol, with its dual objective of emissions reduction and sustainable development. Smallholder systems have not developed in areas where enabling conditions do not exist. A CDM project that facilitates a minimum threshold of enabling conditions that make smallholder agroforestation possible should qualify for C credits. To secure smallholder confidence, the agroforestry systems promoted through a CDM project must be socially and economically viable independent of C payments. To assure system productivity and profitability, projects should provide farmers with technical and marketing assistance. Additionally, project sites should meet the following preconditions: areas of underutilized low-biomass landuse systems available for rehabilitation; smallholders interested in tree farming; accessible markets for tree products; supportive local governments; sufficient infrastructure; and transparent and equitable relationships between project partners. Questions of leakage and additionality should not be problematic and can be addressed through the project design, establishment of quantifiable baseline data and facilitating enabling conditions. However, smallholder-focused CDM projects would have high transaction costs. The subsequent challenge is thus to develop mechanisms that reduce the costs of: (a) making information (e.g., technology, markets) more accessible to multiple clients; (b) facilitating and enforcing smallholder agreements and (c) designing feasible monitoring systems.     

有限约束的Rabenau-Lin区域增长模式

区域发展动力学模式有关研究揭示了以下两个十分重要的区域增长原则:区域发展第一原则:在区域竞争中,应以提高投资环境竞争力为第一,以提高资本增长指数为第二,以提高劳动力增长指数增长为第三;区域发展第二原则:在有限的环境资源约束下,如果区域的平均利率低于区域外的平均水平,要保证区域经济的稳定,必须保障资本的增长指数小于1。     

Potential economic impact of introduction and spread of the red imported fire ant, Solenopsis invicta, in Hawaii

Globally, many invasive alien species have caused extensive ecological and economic damage from either accidental or intentional introduction. The red imported fire ant, Solenopsis invicta, has created billions of dollars in costs annually, spreading as an invasive species across the southern United States. In 1998, the red imported fire ant spread into California creating a highly probable future introduction via shipped products to Hawaii. This paper presents the estimation of potential economic impacts of the red imported fire ant (RIFA) to the state of Hawaii. Evaluation of impacts focuses on the economic sectors of (1) households, (2) agriculture (cattle and crop production), (3) infrastructure (cemeteries, churches, cities, electrical, telephone, and cable services, highways, hospitals and schools), (4) recreation, tourism and business (hotels/resort areas, golf courses, commercial businesses and tourists), and (5) government expenditures (with minimal intervention). The full annual economic costs of the red imported fire ant to Hawaii are estimated (in US$ 2006) to be $211 million/year, comprised of $77 million in damages and expenditures and $134 million in foregone outdoor opportunities to households and tourists. The present value of the projected costs of RIFA over a 20-year period after introduction total $2.5 billion. RIFA invasions across the globe indicate that economic cost-effective action in Hawaii entails implementation of prevention, early detection and rapid response treatment programs for RIFA.     

Value of maternal serum unconjugated oestriol measurement in prenatal screening for Down's syndrome

We compared the medical and financial cost-effectiveness of prenatal serum screening for Down's syndrome using maternal age, serum alpha-fetoprotein and human chorionic gonadotrophin with and without the use of unconjugated oestriol. The use of unconjugated oestriol is medically more cost-effective than screening without it at all levels of detection. The actual performance depends on whether gestational age is estimated using ‘dates’ or an ultrasound scan. At a detection rate of 60 per cent, the proportion of unaffected fetal losses per case diagnosed at amniocentesis is about 22 per cent less if gestational age is estimated using dates (time since the first day of the last menstrual period) and about 47 per cent less if it is based on an ultrasound scan examination. At this detection rate, the inclusion of unconjugated oestriol increases costs by about £2k per case diagnosed (£36k instead of £34k) if gestational age is estimated using dates, but it is no more expensive if gestational age is measured from an ultrasound scan examination (indeed, it is more cost-effective at detection rates above 60 per cent). Since there is little change in the financial cost with the inclusion of unconjugated oestriol, for the improved medical performance of screening, it is worthwhile including it in the screening test.     

粮食增产寄希望于中低产田改造

广东省增加粮食产量的关键是提高单产，改造中低产田是提高单产的最有效途径．本文回顾了一年来广东省农建改低的工作，指出今后应进一步提高认识，高标准搞好农田基本建设，为广东农业实现现代化打下坚实的基础．为搞好农田基本建设，必须切实加强领导．有计划有步骤地认真做好各方面的工作．     

Plant vintage, technology, and environmental regulation

We use data on productivity and pollution abatement costs at individual pulp and paper mills to test whether the impact of environmental regulation on productivity differs by plant vintage and technology. Plants with higher pollution abatement costs have significantly lower productivity levels. This relationship differs greatly based on a plant's technology, with productivity at integrated mills being greatly affected by abatement costs, while the impact at non-integrated mills is negligible. Plant vintage does not seem to matter, with older and newer plants showing similar impacts. Reported abatement costs appear to substantially understate the true costs of abatement. Accounting for the impact of technology differences makes some difference in the estimated overall impact of environmental regulation.     

Project-Based Emissions Trading: The Impact of Institutional Arrangements on Cost-Effectiveness

In this paper we demonstrate that the institutionalarrangement (or: design) of Joint Implementation (JI) and the CleanDevelopment Mechanism (CDM) has a decisive impact on theircost-effectiveness. We illustrate our arguments by statistically analyzing thecosts from 94 Activities Implemented Jointly (AIJ) pilot phase projects aswell as by adjusting these data on the basis of simple mathematicalformulas. These calculations explicitly take into account the institutionaldifferences between JI (sinks, no banking) and the CDM (banking, no sinks)under the Kyoto Protocol and also show the possible effects on credit costsof alternative design options. However, our numerical illustrations shouldbe viewed with caution, because AIJ is only to a limited extentrepresentative of potential future JI and CDM projects and because creditcosts are not credit prices. Some of the main figures found in this study are:an average cost figure per unit of emission reduction for AIJ projects of 46dollar per ton of carbon dioxide equivalent ($/Mg CO₂-eq), anaverage potential JI credit cost figure which is lowered to 37$/Mg CO₂-eq by introducing banking and an average of 6$/Mg CO₂-eq per credit for potential low-cost CDM projects whichincludes sinks. However, at CoP6 in November 2000 in The Hague (TheNetherlands), the Parties to the Framework Convention on Climate Change(FCCC) did not (yet) reach consensus on the institutional details of theproject-based mechanisms, such as the possible arrangement of early JIaction or the inclusion of sinks under the CDM.     

运用资源动态调控体系内化环境成本

生产、消费的环境成本外部性是全球性生态环境问题产生的重要根源之一。在体现资源生态价值的基础上，建立、运用资源动态调控体系(DRSR)、减少资源消耗、减轻环境负荷是绿化传统产业、实现可持续发展的重要经济手段之一。本文就运用资源动态调控体系，内化环境成本、改善环境状况的问题提出个人观点，以供商榷。